The present disclosure relates to a stator assembly of a gas turbine engine and, more particularly, to a cooling system of the assembly having a variable cooling flow mechanism and method of operation.
Gas turbine engines, such as those that power modern commercial and military aircraft, include a fan section to propel the aircraft, a compressor section to pressurize a supply of air from the fan section, a combustor section to burn a hydrocarbon fuel in the presence of the pressurized air, and a turbine section to extract energy from the resultant combustion gases and generate thrust. The turbine section typical includes a stator assembly and a rotor assembly. The stator assembly includes a plurality of vanes that direct hot gases toward a plurality of blades of the rotor assembly. The stator assembly further includes a cooling system often referred to as a tangential on-board injector (TOBI) as one example. The TOBI delivers cooling air to the rotor assembly for cooling of a rotor disk and the attached blades.
Known cooling systems, such as the TOBI, are generally not capable of adjusting cooling air flow. The non-adjustable TOBI typically supplies the rotor assembly with the desired flow at high-power design point. The high-power design point results in a TOBI which may provide too much cooling flow at low power. Overcooling the rotor assembly at low power may increase the transient thermal stress in the rotor assembly resulting in the need for a compensated, heavier, rotor assembly. Thus, there exists a need for improved thermal management of the rotor assembly.